Time-scale analysis of acoustic scattering by elastic spherical shells for impulse sources. Analyse temps-echelle de la diffusion acoustique par des coques spheriques elastiques en regime impusionnel.

Ginette Saracco (1, 2) , Claude Gazanhes (1) , Jean Sageloli (1) , Jean-Pierre Sessarego (1)

1 LMA - Laboratoire de Mécanique et d'Acoustique [Marseille]
2 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement

Time-frequency methods, such smoothed Wigner-Ville transforms, have already been used in studies of the possibility of characterizing scatterers of simple geometric shape. We present here results obtained with the help of a time-and-scale method, the so-called wavelet transform. This transform is used here to analyze results from a scattering experiment on spherical elastic shells, in water. The results obtained are as yet preliminary and semi-quantitative. They indicate however convincingly that certain physical quantities such as type of waves, group velocity, and dispersion laws can be estimated with the help of wavelet methods.

Mots clés: Time-scale analysis; complex wavelet transform; time-frequency method; ridge; squeleton; acoustic scattering; impulse source; spherical elastic shells; Wigner-Ville transform; group velocity; wave front; frequency modulation laws; amplitude modulation laws; stationary phase point; asymptotic method; dilation parameter

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Ginette Saracco, Claude Gazanhes, Jean Sageloli, Jean-Pierre Sessarego. Time-scale analysis of acoustic scattering by elastic spherical shells for impulse sources. Analyse temps-echelle de la diffusion acoustique par des coques spheriques elastiques en regime impusionnel.. Journal d'Acoustique, 1990, 3, pp.381-392. ⟨hal-00018902⟩